Seal line bulkhead view 30l dry bag windowed easy sliding bag for use in hatches product details the waterproof bulkhead view dry bag is designed to efficiently stow in boat hatches and cramped compartments while the integrated window makes it easy to identify contents and the discreet purgeair tm valve vents any trapped air helping optimize space usage purgeair tm equipped new waterproof valve helps the bag compress further once its been sealed see inside translucent win